1. Field of the Invention
This invention relates to a method and apparatus for the modification of climatic conditions by the generation and controlled dispersal of a fog, i.e. fine water droplets suspended in the air.
2. Description of the Prior Art
Artificially created fogs are useful to control climatic conditions in and above foliage in several situations. For example on a hot, dry, still day a fog generated and directed over an area of foliage will cool and humidify the ambient air and in so doing can reduce fruit scorch for instance. Also in hot weather the uptake of water by roots sometimes cannot keep pace with the loss of water from the leaves. An artificial fog or mist can provide foliar irrigation and reduce stress on the plant, tree etc.
However, probably the greatest economic need for modification of climatic conditions is the need to create artificial fogs to counter the effects of radiation frosts where the foliage temperature can plunge below 32 degrees Fahrenheit causing freeze damage to the foliage at a temperature dependent on the particular crop, plant, tree etc.
In U.S. Pat. No. 4,039,144 filed by Thomas R. Mee, assignor to Mee Industries Inc. a method of artificially generating a fog and a considerable amount of the theory behind frost control is discussed. It will be assumed the reader of this specification is familiar with the contents of that patent specification.
Very briefly, U.S. Pat. No. 4,039,144 relates to the generation of a fog at a pre-selected location or locations and wind drift is utilized to convey the fog into and over the foliage to be protected. Difficulties have been experienced with this arrangement firstly because in many geographical locations wind drift is not predictable and secondly because the depth of the fog layer which is economically achieved is insufficient to provide the degree of radiation protection desirable because the cost of generating the fog at a sufficiently large height above the foliage is too high.
Therefore, the prior art discloses methods and apparatus for fog generation but none provides acceptable control of the position of the fog generated.